For most young patients, Children's Hospital is a place they visit briefly, then consign to their memories. But for some, Children's is a constant presence, the place that keeps them alive. My assistant,Julia Feldmeier, recently spent time with the regulars in the dialysis unit.

You're a hemodialysis patient sitting in a hospital room, hooked up to a giant computerized filter that does the work that your kidneys won't. You do this four hours a day, three days a week.

How do you pass the time?

You study. You read. You draw, sleep, watch television. And among fellow dialysis patients and doting nurses, you sass.

It's good-natured chiding, the familial kind.

It starts with "King Man," a 17-year-old dialysis patient and self-described "celebrity" at Children's. A 14-year-old girl hooked up to a machine across the room hears this and rolls her eyes.

"See? She adores me," King Man says.

"I what? Ugh. Please don't let him say that."

King Man grins wickedly. No offense taken.

King Man is Tyrone L. King Jr.Armstead, a high school senior from Suitland who earned his nickname about 13 years ago when he was needle-phobic and Mary Rose Fragale, a 21-year veteran nurse in the dialysis unit, crowned him with a Burger King hat for facing his fears.

Mary Rose is still here, as is Tyrone, who returned to the dialysis unit in 2005 after a kidney transplant failed. It's hard to say who has whom wrapped more tightly around the other's finger. "We're like family," Tyrone says.

And how. There are five hemodialysis patients in Tyrone's Monday-Wednesday-Friday shift (there are 16 hemodialysis patients total, seen on alternate days) and at least two nurses on hand to monitor them. These are perhaps the only people who truly understand the restrictive life that a dialysis patient leads. The patients follow a regimented diet that limits their potassium intake, so such foods as bananas, potatoes and chocolate are a luxury. No dark sodas and no fast food.

Most dialysis patients are unable to urinate, so they retain fluids until their next treatment. Faces get puffy and chests cramp. Although patients are supposed to attend school on the morning of treatment, many don't feel well enough to go.

Dialysis itself can be rough: In bad cases, when patients haven't followed the proper diet, "it's almost like having a horrible flu for four hours," says Carol Carr, a nurse in the dialysis wing. Blood pressure drops. Wooziness and cramps ensue. Vomiting can occur.

Where a normal kidney works 168 hours a week, sifting waste and water from the blood, dialysis attempts to accomplish this in roughly nine to 12 hours. "At best, it can achieve about 10 percent of what a normal kidney can do," says Dr. Kevin McBryde, a doctor in the nephrology division at Children's.

Kidney transplants aren't perfect -- they come with their own set of issues -- but they bring hope for a better life. For children, the average wait for a donor is about 18 months, according to Dr. McBryde; adults wait an average of six years.

As with any waiting game, the clock ticks faster when there are distractions, people to make us forget the time. It's Mary Rose cajoling a 14-year-old girl into drinking her protein drink -- "come on, just hold your nose" -- and Tyrone cajoling Mary Rose into having her picture taken, a thought that appeals as much to her as the protein drink does to the 14-year-old.

But our girl drinks, and Mary Rose poses.

"The things I do for you, King Man."

"That's why I love you, Mary Rose."

How to Help

The dialysis kids and their nurses feel a camaraderie for one another. I like to think there's a similar kinship among Washington Post readers who support our annual fund drive for Children's Hospital. Here's how you can join the club:

To donate, make a check or money order payable to "Children's Hospital" and mail it to Washington Post Campaign, P.O. Box 17390, Baltimore, Md. 21297-1390. To donate online using a credit card, go to http://www.washingtonpost.com/childrenshospital. To contribute by phone using Visa or MasterCard, call 202-334-5100 and follow the instructions on the recording.